Review of Instrumentation

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Review of Instrumentation
Instrumentation Staff
William Brey Group Leader Peter Gorkov Solid
State and Imaging Probes Kiran Shetty Series
Connected Hybrid (SCH) Jason Kitchen Mechanical
Engineer (started May 09) Richard
Desilets Machinist
Projects

• Imaging (presented by Sam Grant)
• Low E Probe Development
• VTMAS Capability
• Low ? Probe Development
• Shims and Field Regulation for SCH
• Superconductive RF Probe Development

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Low-E Probe Development at the NHMFL
100 mM NaCl 20 mM TmDOTP _at_ 600 MHz

• Independent loop gap resonator for 1H channel
  reduces electric field, sample heating
• Double-tuned solenoid optimized for lower
  frequency (has more turns)

(horizontal axis values include duty cycle)

• Highlights and Milestones
• Static probes developed for flat (270 ?L), and
  static bicelle (5 and 6.6 mm) samples for 600 and
  900. Users include Cross, Veglia, Cotten,
  Ramamoorthy, Lorigan.
• MAS probe developed for 4 mm / 750 MHz (Long).
• Bruker adapted technology for Efree probe
  sponsored postdoc at MagLab for 2 years
  (2007-2009).

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Triple Resonance Low-E Probe Development

• Solenoid uses Cross-Waugh network with lumped
  element traps, balanced on both XY channels.
• Plug in and screw down inductors and capacitors
  allow rapid retuning.
• Revolution NMR stators have been optimized to
  accommodate long low-E inserts.
• Prototype MAS probe for 600 MHz. Follow on
  probes will include 900 MAS, 600/900 static, 750
  MAS.

Supported by User Collaboration Grant
Instrumentation and Techniques to Use 14N NMR to
Probe the Structure of Biomolecules, Brey, Gan
Gorkov, Hung
14N/13C/1H Low-E MAS Probe, 3.2 mm 600 MHz
4
Balanced Tuning in Narrow Bore 830 MHz Magnet
7 mm and 4 mm MAS probes

• Balanced tuning reduces voltages, suppresses
  arcing, allows doubling of B1.
• Insertable capacitors allow practical balanced
  circuit in 32 mm bore of 830 magnet (see photo).
• For MQMAS (4 mm rotor), multiple quantum
  excitation efficiency and S/N ?B1 thereby
  doubling the S/N for the balanced version.
• 7 mm probe (shown at right) always needed more B1.

unbalanced
balanced
Z. Gan, P.L. Gor'kov, W.W. Brey, P.J. Sideris,
and C.P. Grey, J. Magn. Reson. 200, 2-5 (2009).
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Improved VT MAS Capability for 900
Routine Spinning to Below -150 ?C

• LN2 system cools probe quickly from room temp to
  -150 ?C (123 K) with N2 flow of 1200 L/hr (42
  scfh)
• Minimal icing allows safe, reliable operation
• Auto refill controller for continuous operation
• Refills of 45 L lab cryostat (from 40 to 60)
  occur about every 3 hours (9 L transfer per
  refill).
• Tied for Best Senior Project of 2009 in FAMU-FSU
  Mechanical Engineering Department

Team members (L-R) Jason Kitchen, Rebecca
Altman, Jessica Vanterpool, Zachary Stevenson
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How to get temperature stability during refills
from a Doty cooling system

1. Shield the precooling coils from venting gas.
   Boiloff increases during fills, reducing outlet
   gas temperature. The increase in cryogen
   consumption was only 10.
2. Pressurize the supply dewar only during
   transfers. The LN2 in a self-pressurized
   cryostat at 22 psig is at 86 K, not 77 K, which
   changes the bath temperature during a transfer.
3. Adjust the PID coefficients for the VT
   controller. The Bruker edte autotune gives
   very low values of P that compromises the
   response.

Insulation on precooling coils
Refill fluctuations reduced from 3 ?C to 0.3 ?C
Original
Modified
User/Collaborators Riqiang Fu and Naresh Dalal
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36 T in 2013 the Series Connected Hybrid

• We are developing
• Field regulation (Schiano collaboration)
• Active shims (MST collaboration)
• RF Probes
• Proposal to NSFs MRI-R2 call for 1.6 GHz
  console was submitted August 2009.

The SCH will have less field noise and better
homogeneity (after correction) than other powered
magnets.
Supported by NSF through DMR-0603042
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Resistive Shims for SCH
Field Correction of Keck 25 T Magnet at 7 T
Difference Mapping Allows Correction of
Fluctuating Fields
High current power supplies
50 ppm/150 A water cooled 6-term shim coil
Painter, T.A. Bird, M.D. Bole, S.T. Trowell,
A.J. Shetty, K.K. and Brey, W.W., Resistive
Shims for High-Field Resistive and Hybrid
Magnets, IEEE Trans. Appl. Supercond., 18 (2),
579-582 (2008)
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Field Regulation for SCH
Keck Noise Spectra

• Collaboration with Prof. Jeffrey Schiano at Penn
  State.
• Temperature-regulated preamplifier has reduced
  drift.

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NHMFL/Bruker 1 mm HTS Probe

• Total mass sensitivity gt3x that of the best
  commercial micro-solenoid!
• Meets standard requirements for
• Non-spinning lineshape (50/.55/.11) 0.88 /
  13.9 / 20.9 Hz
• Pulse lengths 1H 9.5 ?s,
  13C 15 ?s, 15N 48 ?s

12 mm
Funded by NIH Now part of NHMFL User Program

• On-line since September, 2005
• Triple-resonance (1H, 13C, 15N, 2H)
• 600 MHz
• Minimum sample volume 7.5 ?L
• Active sample volume 6.3 ?L

Brey, W.W. Edison, A.S. Nast, R. Rocca, J.
Saikat Saha, S. and Withers, R.S., Design,
Construction and Validation of a 1 mm Triple
Resonance High-Temperature Superconducting Probe
for NMR, J. Magn. Reson., 179 (2), 290-293 (2006)
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High Temperature Superconductor (HTS) Probe
Technology
Vacuum wall
Spiral for low freqs
Lattice-matched substrate
1H
Epitaxial Y1Ba2Cu3O7-? (YBCO)
Single-sided Resonators
Helmholtz Pair

• Technology Limitations
• Single frequency resonators
• Single sided devices only
• Flat substrates only

HTS coil resistance less than 1/10 of
conventional cryoprobes!
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R01 Funded July 2009 to Develop 1.5 mm Dual
Sensitive13C/1H Superconductive Cryoprobe
Mag Lab NMR User Program Edison (PI, NMR) Brey
(RF Design)
Mag Lab Applied Superconductivity Center David
Larbalestier
Varian, Inc. Rich Withers Rob Nast Tom DeSwiet

• Collaborative materials and RF development toward
  more compact, sensitive, efficient and
  homogeneous triple resonance coil sets.
• Coil/sample optimization to reduce loading and
  increase sensitivity.
• Magnet Lab and Varian matching funds to support
  purchase of Varian console.

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Instrumentation Highlights 2009

• Jason Kitchen hired to support user programs.
• VT MAS functioning to -150 ?C on 900 UWB stable
  to 0.3 ?C
• Balanced low-? probes for 830 narrow bore double
  B1.
• HTS probe development funded by Edison R01
• SCH Console application through MRI-R2
• Difference map of Keck powered magnet to 1 ppm